670 FXUS63 KGRB 101747 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 1247 PM CDT Wed Oct 10 2018 Updated aviation portion for 18Z TAF issuance .SHORT TERM...Today...Tonight...and Thursday Issued at 414 AM CDT Wed Oct 10 2018 Heavy rain potential will continue through this afternoon, especially over central and north-central portions of the CWA. The Flood Watch continues for locations to the northwest of a line from roughly Northern Marinette County to Portage County although heavy rainfall totals are possible outside of those areas as well. Satellite imagery and surface observations continue to show widespread cloud cover across much of the Western Great Lakes region, with the exception of some breaks in the clouds over southeastern WI. Radar trends continue to show moderate to occasionally heavy showers and thunderstorms sliding across portions of central and north central WI stretching south into eastern IA and northeastern Missouri. Surface observations and webcams continue to show patchy to widespread fog with visibilities around a mile across portions of the CWA this morning. Today: An intensifying low pressure system will slide from Iowa northeast to Upper Michigan through this evening. Additional upper- level energy will slide into the area throughout the day helping to intensify the low and keep showers and thunderstorms in place. As the low passes through the area, the associated cold front will pass through around 00Z this evening. Continued deep layer moisture will keep the potential for heavier rainfall across the area with up to and additional inch or so possible through this evening. The additional rainfall on saturated ground will keep the flooding risk in place through much of the day as area rivers are running near to slightly above bankfull across many locations. This will lead to the continuation of the Flood Watch through late this afternoon/early evening at 00Z/11th. Some drier air may try to filter in across the western portion of the Watch area by mid afternoon as a dry slot approaches. If this happens, some of the Watch may be trimmed back later in the day. If enough clearing takes shape this morning into the early afternoon around the Fox River Valley, then there could be a couple strong to possibly severe storms this afternoon; however, instability is not expected to be as favorable today. Deep layer shear values are progged to be around 30 to 40 kts, so any breaks in the cloud cover would quickly allow for a couple storm to become strong to severe ahead of the cold front. Again, the better chance will be over the southeastern portions of the CWA, where SPC has placed the Marginal Risk. Small hail and gusty thunderstorms winds will be the main threats this afternoon. High temperatures will range from the 40s over north- central WI to the 60s to low 70s around the Fox River Valley. Tonight into Thursday: The low will slowly lift off to the northeast through this time period, allowing the heavier rainfall to end from the southwest. There will likely be some linger wraparound rainfall over the north-central WI along with linger cloud cover across much of the area tonight. Otherwise, blustery conditions can be expected as wind gust to in the 30 to 40 mph range across much of the CWA tonight into at least Thursday morning. This will also usher in some much cooler air, making for uncomfortable outdoor conditions tonight into Thursday. Overnight lows will drop into the 30s to around 40 tonight with highs on Thursday expected to be in the upper 30s to the low 40s. .LONG TERM...Thursday Night Through Tuesday Issued at 414 AM CDT Wed Oct 10 2018 A cool pattern will be shaping up across the region during this part of the forecast, thanks to persistent troughing over the western Great Lakes, and reinforced with a building ridge over the west coast of North America. Forecast concerns mainly revolve around temperatures, with some small precip chances sprinkled in. Thursday night through Friday night...High pressure will be shifting east over the northern Mississippi Valley and towards the region on Thursday night. Due to cyclonic flow and enhanced moisture above 850mb, clouds are likely to linger across much of the area at the start of the evening. However, they should gradually retreat north through the night. But even with a 10-15 mph wind, temps are likely to approach the freezing mark over the Fox Valley and Lakeshore areas where lows are projected to fall between 30-35 degrees. Weak shortwave energy will move across the region on Friday and will likely result in partly to mostly cloudy skies, but a dry wedge in the mid-levels should keep the area dry. Below normal temps will continue with highs in the low to mid 40s. Conditions appear more favorable for a frost/freeze over the Fox Valley and Lakeshore on Friday night due to less wind and cloud cover expected. Temps are again expected to fall into the low to mid 30s in this area. Rest of the forecast...Although the system for the weekend has shifted south towards the Ohio Valley, the northern stream looks more potent, and will send a cold front across the region on late Saturday afternoon into Saturday night. A chance of light precip will accompany the front, which should consist of mostly rain, though a few snowflakes could mix in over north-central WI late Saturday night into Sunday morning. After another cool day on Monday, a brief warm up could occur on Tuesday but with a chance of rain returning. && .AVIATION...for 18Z TAF Issuance Issued at 1238 PM CDT Wed Oct 10 2018 A large area of showers will gradually shift east across the region during the afternoon, and exit far northeast WI by early evening. A warm front has moved into the far south part of the forecast area, but temporary improvements in flight conditions have been offset by reduced cigs/vsbys in moderate rain. The bottom line is that most of the region will see MVFR/IFR conditions tonight, with some LIFR ceilings at times in northern WI this afternoon anf evening. Widespread MVFR ceilings are anticipated on Thursday morning. Winds will become gusty out of the southwest and west tonight into Thursday as colder air filters into the area and the pressure gradient tightens. Gusts to around 30 kts are expected during that time period. There could be a mix of rain/snow showers over the far north late tonight into Thursday morning, but plan to keep any mention of snow out of the RHI TAF site for now. && .GRB WATCHES/WARNINGS/ADVISORIES... Flood Watch until 7 PM CDT this evening for WIZ005-010>013- 018>021-030-031-035-036. && $$ SHORT TERM.....Cooley LONG TERM......MPC AVIATION.......Kieckbusch